Very odd programming trouble

["J.A.Serralheiro" <mrserra@ci.uc.pt>]

/*Hi folks. Heres a very odd trouble ( for me at least)
  I was reading a book where it was stated that
 "     char *ptr = "text";   " is an allowed declaration and that
  the compiler automatically allocates space for the string text and for the
  \0 terminating character ( true) . 
  I decided to try it with strcpy(char *dest, const char *src) and 
  there seems to be a problem. Whenever dest is a pointer declared as above
  theres a segmentation fault. I tried the code bellow which suffers from 
  exactly the same. The problem seems to relly In the expression
   "while ( (*dest++ = *src++)!= '\0' )" .
I tried all the combinations with strcpy, but only this one gave odd results.
  It seems that the compiler as some dificulties assigning *dest++ = *src++
  when dest is a char *ptr = "kljdflg". But when src is this kind of
pointer and dest is an array ( as so declared) ,
  it works fine. Its not very usual to declare strings this way
  but its stated as ansi compliant, and the compiler silently accepts it
without any warnings.
  The code is set to the particular combination where a SIGSEGV is generated
  dest=s1; /*char *s1 = "ldksj" 
  src=string; /*char string[]= "dflkjg"*/

Can someone solve this mistery ?

#include <stdlib.h>
#include <stdio.h>
/*#include <string.h>*/

	      
// this is strcpy source code borrowed from string.h with another name
char *strc(char *dest,const char *src)
{
	char *tmp = dest;

        while ( (*dest++ = *src++)!= '\0' );

	return tmp;
}

int main ( void ) {
   
   char *s1 = "frase_1";
   char *s2 = "frase_2";
   char string[] = "frase_3";
   char *dest, *src;
   int i;
   
   //See if theres a terminating character int the string
   for( i = 0; i != strlen(string)+2; i++) 
      printf( " s1[%x]=%d string[%x]=%d  \n",
	           s1+i, *(s1+i), string+i, string[i] );
   //show s1 and string address
   printf( "s1 %x string %x", s1, string);
   fflush(stdout); 
   //strcpy simulation
   dest=s1;
   src=string;
   //check if assignment is valid
   printf(" dest %x src %x ", dest, src );
   fflush(stdout);
   //start copy
   while ( (*(dest++) = *(src++)) != '\0' ) {
      // want to see the address progression of dest and src
      printf( "\n dest[%x]= src[%x]= ", dest, src );
      fflush( stdout );
   }
   // the result
   printf( "\n ret dest address %x  val %s  \n", s1, s1 );
}